Long-term fire retardant with an organophosphate and methods for making and using same

ABSTRACT

A forest fire retardant composition is substantially free of ammonium and includes an organophosphate derived from (i) a phosphorylation agent and (ii) an organic molecule comprising at least two hydroxyl groups. The organophosphate may contain at least one phosphate ester bonded to an organic molecule, wherein the organic molecule comprises at least one monomer unit of about 2 to 40 carbon atoms. Preferably, at least 90% of the functional groups of the organophosphate is a phosphate ester group. The composition may also include a salt, including magnesium salt and/or calcium salt. The anion in the salt may be hydroxide, carbonate or phosphate. The salt may be an anhydrous salt, a salt hydrate, or a combination of both. The composition is effective in suppressing, retarding, and controlling forest fires while exhibiting corrosion resistance and low toxicity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/031,024 filed Sep. 24, 2020, which is a bypass continuation of PCTApplication No. PCT/US2020/036367 filed Jun. 5, 2020, each of which ishereby incorporated herein by reference in its entirety. PCT ApplicationNo. PCT/US2020/036367 claims a priority benefit to U.S. provisionalapplication Ser. No. 62/858,640, filed on Jun. 7, 2019, 62/989,350 filedon Mar. 13, 2020, 63/024,040 filed on May 13, 2020, and 63/028,765 filedMay 22, 2020, which are incorporated herein by reference in theirentirety.

BACKGROUND

Long-term retardants contain retardant salts that alter the way a forestfire burns, decrease the fire intensity, and slow the advance of theforest fire. Long-term retardants may be available as wet or dryconcentrates that are mixed with water thereby improving water'seffectiveness and ability to cling to fuels, over a long period of time.Long-term retardants may be colored with iron oxide, fugitive pigments,or remain uncolored.

In the “Ecological Risk Assessment of Wildland Fire-Fighting Chemicals:Long-Term Fire Retardants” (September 2017), hereby incorporated byreference in its entirety, the United States Forest Service (“USFS”) hasestablished a chemical toxicity risk assessment for fire-fightingchemicals currently approved for use by the USFS. The USFS uses avariety of fire-fighting chemicals to aid in the suppression of fire inwildlands. These products can be categorized as long-term retardants,foams, and water enhancers. This chemical toxicity risk assessment ofthe long-term retardants examines their potential impacts on terrestrialwildlife, plant, and aquatic species.

Further, in Specification 5100-304d (Jan. 7, 2020), SupersedingSpecification 5100-304b (July 1999), Superseding Specification5100-00304a (February 1986), entitled “Specification for Long TermRetardant, Wildland Fire, Aircraft or Ground Application,” herebyincorporated by reference in its entirety, the United States Departmentof Agriculture (“USDA”) Forest Service has established the maximumallowable corrosion rates for 2024T3 aluminum, 4130 steel, yellow brassand Az-31-B magnesium. The corrosivity of forest fire retardants, inconcentrate, to aluminum, steel, yellow brass and magnesium must notexceed 5.0 milli-inches (“mils”) per year as determined by the “UniformCorrosion” test set forth in Section 4.3.5.1 of the USDA Forest ServiceSpecifications. The Forest Service Specifications identify the maximumamount of corrosion acceptable when both the retardant concentrate andits diluted solutions are exposed to each metal indicated above attemperatures of 70° Fahrenheit (“F”) and 120° F. in both totally andpartially immersed configurations. The maximum allowable corrosivity ofaerially applied fire-retardant diluted solutions to aluminum is 2.0mils per year (“mpy”) and the maximum corrosivity to brass and steel is2.0 mpy when partially immersed and 5.0 when tested in the partiallyimmersed condition. In the partially immersed configurations, one-halfof the coupon is within the solution and one-half is exposed to thevapors in the air space over the solution.

SUMMARY

The invention relates generally to fire retardant compositions and moreparticularly to long-term fire retardants suitable for use in direct orindirect attack of forest fires.

Embodiments of the present technology include a forest fire retardantcomposition. The forest fire retardant composition is substantially freeof ammonium. The forest fire retardant composition includes anorganophosphate and a corrosion inhibitor. The organophosphate isderived from a phosphorylation agent and an organic molecule comprisingat least two hydroxyl groups. The organic molecule may comprise apolymer. The organic molecule may comprise at least one of an alkyleneglycol derivative, a glycerol derivative, or a saccharide derivative.The alkylene glycol derivative may comprise at least one of ethyleneglycol, polyethylene glycol, propylene glycol, or polypropylene glycol.The glycerol derivative may comprise at least one of glycerol,diglycerol, or triglycerol. the saccharide derivative may comprise atleast one of glucose, sucrose, fructose, xanthan, cellulose,methylcellulose, ethylcellulose, or alginate. The phosphorylation agentmay comprise phosphoric acid or phosphoryl chloride.

At least 50% of the functional groups of the organophosphate maycomprise a phosphate ester group. Alternatively, at least 75% of thefunctional groups of the organophosphate may comprise a phosphate estergroup. Alternatively, at least 90% of the functional groups of theorganophosphate may comprise a phosphate ester group.

In another embodiment, the forest fire retardant composition that issubstantially free of ammonium and includes an organophosphatecomprising at least one phosphate ester bonded to an organic molecule,and a corrosion inhibitor. The organic molecule in this forest fireretardant composition comprises at least one monomer unit of about 2 to40 carbon atoms. The organic molecule may comprise at least one ofglucose, fructose, glycerol, diglycerol or triglycerol.

The organophosphate may comprise a phosphorylated polymer containingless than 12,000 monomer units. The ratio of phosphate esters to monomerunits (phosphate esters:monomer units) in the organophosphate may beabout 0.1:1 to about 10:1. The monomer unit may comprise a linear chainof atoms. The monomer unit may comprise at least one six-membered cyclicring. The monomer units may be bonded together through ether linkages.The monomer unit may comprise at least one of a saccharide, a glycerol,an ethylene glycol or a propylene glycol. The organophosphate may bepresent in the forest fire retardant composition from about 5% to about80% by weight.

The forest fire retardant composition may further comprise a saltcomprising at least one of magnesium salt, calcium salt, magnesiumcalcium salt, or a combination thereof. The anion in the salt maycomprise at least one of hydroxide, carbonate, or phosphate. The saltmay comprise magnesium salt, which may be anhydrous magnesium salt ormagnesium salt hydrate. The magnesium salt may comprise at least one ofMgCO3, Mg3(PO4)2, Mg5(CO3)4(OH)2(H2O)4, or Mg3(PO4)2(H2O)8. As analternative to using a magnesium salt, or in addition to using amagnesium salt, the salt may further comprise calcium salt, which may beanhydrous calcium salt or calcium salt hydrate. The calcium salt maycomprise at least one of CaCO3, Ca3(PO4)2, Mg3Ca(CO3)4, orCa3(PO4)2(H2O)2. The magnesium salt and calcium salt may be present inthe composition in a weight ratio (magnesium:calcium) from about 5%:95%to about 95%:5%. The salt may be present in the composition in a weightpercent of about 20% to about 70% relative to the amount oforganophosphate in the composition.

The corrosion inhibitor in the forest fire retardant composition may bepresent in a weight percent of 0.5% to 4.0% relative to the amount oforganophosphate in the forest fire retardant composition.

The forest fire retardant composition may further comprise a pigmentpresent in a weight percent of about 0.25% to about 6.0% relative to theamount of organophosphate in the forest fire retardant composition. Theforest fire retardant composition may further comprise a dye present ina weight percent of about 0.02% to about 3.0% relative to the amount oforganophosphate in the forest fire retardant composition. The forestfire retardant composition may further comprise a viscosity modifierpresent in the forest fire retardant composition in a weight percent ofabout 0.25% to about 6.0% relative to the amount of organophosphate inthe forest fire retardant composition. The forest fire retardantcomposition may further comprise a surfactant present in a weightpercent of about 0.02% to about 5% relative to the amount oforganophosphate in the forest fire retardant composition. The forestfire retardant composition may further comprise a glow-in-the-darkadditive. The forest fire retardant composition may further comprise abiocide.

The forest fire retardant composition may constitute a liquidconcentrate having an organophosphate concentration of about 15% to 99%by weight. For example, the liquid concentrate may have anorganophosphate concentration of about 20% to about 70% by weight.

The forest fire retardant composition may further comprise water, inwhich case the forest fire retardant composition may constitute a finaldiluted product suitable for use in combating forest fires. The finaldiluted product may have a weight percent of organophosphate of about 5%to 35%. The final diluted product may have a viscosity of about 100 toabout 2,500 centipoise.

In another embodiment, a method of manufacture includes combining, viabatch mixing or continuously mixing, (i) an organophosphate, (ii) acorrosion inhibitor, and (iv) a colorant. The components may furthercomprise a salt comprising at least one of calcium salt, magnesium salt,magnesium calcium salt, or a combination thereof. The salt may be aliquid salt solution.

In another embodiment, a method of manufacture includes receiving aforest fire retardant composition that includes an organophosphate(including at least one of a phosphorylated small molecule or aphosphorylated polymer) and diluting the composition with water, in oneor more diluting steps, to achieve at least one of a liquid concentrateand/or a final diluted product.

In another embodiment, a method of combating a forest fire includesdepositing, via aerial or ground-based application, a forest fireretardant composition containing an organophosphate, a corrosioninhibitor, and water. The step of depositing includes at least one of adirect attack on the fire or an indirect attack before the fire.Combatting a forest fire includes at least one of suppressing,retarding, and/or controlling the forest fire. The step of depositingmay be performed via aerial application from an airplane or helicopter.Alternatively, the step of depositing may be performed via ground-basedequipment. The organophosphate in the forest fire composition depositedmay have a concentration of about 5% to about 35% by weight.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein. It should also be appreciated that terminologyexplicitly employed herein that also may appear in any disclosureincorporated by reference should be accorded a meaning most consistentwith the particular concepts disclosed herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The skilled artisan will understand that the drawings primarily are forillustrative purposes and are not intended to limit the scope of theinventive subject matter described herein. The drawings are notnecessarily to scale; in some instances, various aspects of theinventive subject matter disclosed herein may be shown exaggerated orenlarged in the drawings to facilitate an understanding of differentfeatures. In the drawings, like reference characters generally refer tolike features (e.g., functionally similar and/or structurally similarelements).

FIG. 1 is a flow chart diagram showing the process of making a forestfire retardant composition.

FIG. 2 is a chemical structure of a cellulose monomer with six phosphateester functional groups.

DETAILED DESCRIPTION

In General

As used herein, a dry concentrate means a concentrate that has theappearance of a dry free-flowing powder, a waxy solid, or a greasysolid. A dry concentrate may include small amounts of liquid components,including liquid organophosphate, water, other solvent(s) or aqueoussolutions in concentrations low enough to be substantially adsorbed ontothe dry components, thereby having the appearance of a dry free-flowingpowder, a waxy solid, or a greasy solid. As used herein, a liquidconcentrate means a concentrate that is a liquid. A liquid concentratemay include water, other solvent(s), aqueous solution(s), or anycombination thereof.

Referring to FIG. 1, a forest fire retardant composition 500 can beprovided in various forms. The composition 500 can be provided as a dryconcentrate 501 substantially free of water. Alternatively, thecomposition 500 can be provided as a liquid concentrate 502. The liquidconcentrate 502 may be formed by adding water, other solvent(s) oraqueous solutions to the composition when it is prepared. Alternatively,the liquid concentrate 502 may be formed by adding water, othersolvent(s) or aqueous solutions to the dry concentrate 501.Alternatively, liquid concentrate 502 may be formed when the dryconcentrate 501 is deliquescent, hygroscopic, and absorbs moisture fromthe air or other moisture source. Alternatively, the liquid concentrate502 may include a liquid organophosphate. If the liquid concentrate 502includes a liquid organophosphate, the liquid concentrate 502 mayinclude water, other solvent(s), aqueous solution(s), or any combinationthereof. The composition 500 can also be provided as a final dilutedproduct 503 in a form suitable to fight forest fires via aerial- orground-based application. The final diluted product 503 is formed eitherby diluting the dry concentrate 501 with water or by diluting the liquidconcentrate 502 with water.

Components of the Forest Fire Retardant

The forest fire retardant composition 500 includes an organophosphate.The organophosphate may include one or more phosphate esters bonded toan organic molecule. The organic molecule includes at least one monomerunit of about 2 to about 40 carbon atoms. The organic molecule can be asmall molecule, such as glycerol, diglycerol, triglycerol, glucose orfructose. Alternatively, the organic molecule can be a polymer ofrepeating monomer units up to 12,000 repeating monomer units. Bridgesbetween repeating monomer units may be ether linkages. The monomer unitcan be small and/or linear, such as in polyethylene glycol, or largeand/or cyclic, such as in xanthan. The polymer backbone can bepolyethylene glycol, polypropylene glycol, and/or another linear orbranched chain. Alternatively, the polymer backbone can be xanthan,alginate, cellulose, methylcellulose, ethylcellulose or anotherpolysaccharide. The small organic molecule is preferably triglycerol.The polymer organic molecule is preferably cellulose. The forest fireretardant composition 500 may include one organophosphate or acombination of several organophosphates.

The number of phosphate ester functional groups on the organic moleculecan vary depending on the size of the organic molecule and on the amountof functionalization. Phosphorylated small molecules may befunctionalized with about 1 to about 10 phosphate ester groups.Phosphorylated polymers may be functionalized with a larger number ofphosphate ester groups. Phosphorylated polymers may be functionalized sothat not all monomers have phosphate esters. Alternatively, for example,in instances when the monomer unit is more complex, each monomer unitcan be functionalized with up to 10 phosphate ester functional groups.The ratio of phosphate esters to monomers (phosphate ester:monomer) isabout 0.1:1 to about 10:1, preferably about 0.5:1 to about 8:1, andparticularly about 2:1 to about 6:1. The phosphorylated small moleculeis preferably triglycerol with at least two phosphate ester functionalgroups, and more preferably six phosphate ester functional groups.Alternatively, the phosphorylated small molecule may be functionalizedwith one phosphate ester per monomer unit, as in glycerol phosphate orpoly(glycerol phosphate)_(n), where n is about 2 to about 5, and morepreferably where n is about 3. The phosphorylated polymer is preferablycellulose with 95% of the monomers functionalized with at least onephosphate ester functional group and with each cellulose monomerfunctionalized with about 4 to about 6 phosphate ester functionalgroups. Referring to FIG. 2, the cellulose monomer can have up to 6phosphate ester functional groups.

The organophosphate may be derived from an organic molecule with two ormore hydroxyl groups that has undergone a reaction with aphosphorylation agent. The organic molecule may be at least one of asmall molecule or a polymer, such as a polyol. In a reaction between ahydroxylated organic molecule and a phosphorylation agent, one or morehydroxyl functional groups on the organic molecule may be replaced byphosphate ester groups to produce the organophosphate. The organicmolecule may be an alkylene glycol derivative, such as ethylene glycol,propylene glycol, or polymers of these compounds. Alternatively, theorganic molecule may be a glycerol derivative, such as diglycerol ortriglycerol. Alternatively, the organic molecule may be a saccharide,such as glucose, xanthan, alginate, cellulose, methylcellulose or ethylcellulose. The phosphorylation agent may be phosphoric acid orphosphoryl chloride. The organophosphate may be functionalized so thatthe number of functional groups that are phosphate esters is about 10%to about 99%, preferably about 50% to about 95%, and particularly about85% to about 95%.

Referring to FIG. 1, the composition 500 may begin as a dry concentrate501 substantially free of water. As used herein, “substantially free ofwater,” when referring to the dry concentrate 501, does not refer towater, solvents or other liquids absorbed or adsorbed into the dryconcentrate 501. The dry concentrate 501 may be in the form of a hardsolid, a waxy solid, or a greasy solid. The dry concentrate 501 may haveno more than about 3% by weight of water relative to the total weight ofthe concentrate. The dry concentrate 501 may have an organophosphateconcentration of about 60% to about 99% by weight relative to the totalweight of the concentrate.

The liquid concentrate 502 may be formed by adding water, othersolvent(s) or aqueous solutions to the composition when it is prepared.Alternatively, the composition 500 may be a liquid concentrate 502formed by the addition of water or other solvent to the dry concentrate501. The water may be tap water or water from other convenient watersources. Alternatively, the liquid concentrate 502 may include a liquidorganophosphate. If the liquid concentrate 502 includes a liquidorganophosphate, the liquid concentrate 502 may include water, othersolvent(s), aqueous solution(s), or any combination thereof. In theliquid concentrate 502, the weight percent of organophosphate is about15% to about 99%, preferably about 15% to about 90%, more preferably 20%to 70%, and particularly about 30% to about 60%. For example, the weightpercent of organophosphate in the liquid concentrate 502 is about 35% toabout 55%. In the liquid concentrate 502, water may be present in aconcentration of about 5% to about 70% by weight relative to the totalweight of the concentrate.

The forest fire retardant composition 500 is substantially free ofammonia. Preferably, the organophosphate does not contain any ammoniumfunctionalized compounds. Ammonium-functionalized compounds may causelong-term adverse effects in the aquatic environment. Additionally,ammonium-functionalized compounds may release ammonia gas uponcombustion. Ammonia gas is acutely toxic and may cause burns to the skinand eyes. Additionally, ammonia is toxic to aquatic organisms. Theforest fire retardant composition 500 is less toxic than those forestfire retardants that contain ammonia or ammonium-functionalizedcompounds.

The forest fire retardant composition 500 may further include acorrosion inhibitor. The corrosion inhibitor includes an inhibitor forbrass, iron, aluminum, steel, copper, or magnesium. The corrosioninhibitor for magnesium may include COBRATEC 928, Denatonium benzoate,benzoic acid, Diammonium phosphate, monoammonium phosphate, Wintrol SB25Na, or a combination of the above. The corrosion inhibitor may includeone or more azoles. The corrosion inhibitor may be a Wintrol® SuperAzole Mix (Wintrol® SAM-H90 from Wincom, Inc). The Wintrol® SAM-H90 isdesigned for aqueous application. Wintrol® SAM-H90 provides corrosionresistance in highly corrosive environments caused by halogens, such aschloride. Optionally, Wintrol® SAM-H38Na may be used as the corrosioninhibitor, alone or in combination with Wintrol® SAM-H90. The corrosioninhibitor may be, including but not limited to, sodium selenite, sodiumsilicate, sodium stearate, sodium benzoate, sodium fluoride, sodiumphosphate, magnesium phosphate, magnesium diphosphate,benzotriazole-5-carboxylic acid, benzotriazole, 1,8-naphthalaldehydicacid, octadecylphosphonic acid, sodium dodecyl sulfonate (SDBS),Wintrol® BBT-25Na, Wintrol® BBT, Wintrol® THT-T, Wintrol® THT-35PG,Wintrol® THT-50K, Wintrol® SAM-H90, Wintrol SB 25Na, Wintrol® SAM-H38Na,Wintrol® SAM-H40(OS), Wintrol® SAM-B90, berberine, pyrrolidine riccione,catechin, lysergic acid, carmine, fast green, aniline, triethanolamine,p-chloroaniline, p-nitroaniline, p-methoxyaniline, p-methylaniline, or acombination of the above.

The weight percent of the corrosion inhibitor, relative to the amount oforganophosphate in the composition 500 is about 0.25% to about 5.0%,preferably about 0.5% to about 4.5%, more preferably about 0.75% toabout 4.0%, and specifically about 1.0% to about 3.5%. For example, theweight percent of the corrosion inhibitor, relative to the amount oforganophosphate in the composition 500 is about 1.0% to about 3.0%.

The forest fire retardant composition 500 may include a salt 504,including any salt disclosed in U.S. Patent Application Nos. 62/858,640,62/989,350, or 63/024,040 which are hereby incorporated by reference intheir entirety. The salt 504 may include magnesium salt. The anion inthe magnesium salt may be at least one of hydroxide, carbonate, orphosphate. The magnesium salt may have the formula MgCO₃, Mg₃(PO₄)₂,Mg(OH)₂, or Mg₅(CO₃)₄(OH)₂. The salt 504 may include a mixture of morethan one magnesium salt. The magnesium salt can be anhydrous,substantially free of any hydrate. Alternatively, the magnesium salt canbe a hydrate, substantially free of any anhydrous. Alternatively, themagnesium salt can be a combination of anhydrous and hydrate. Thehydrate may have the formula MgA_(x)(H₂O)_(y), where A is an anion, x isequal to the number of anions in the ionic compound and y is equal tothe number of hydrates. The magnesium salt hydrate is preferablyMg₅(CO₃)₄(OH)₂(H₂O)₄, Mg₃(PO₄)₂(H₂O)₈, or another magnesium salthydrate.

Instead of (or in addition to) magnesium salt, the salt 504 may becalcium salt and/or the salt 504 may be magnesium calcium salt thatincludes both magnesium and calcium cations. The anion in the calciumsalt and/or magnesium calcium salt may be at least one of hydroxide,carbonate or phosphate. The calcium salt may have the formula CaCO₃,Ca₃(PO₄)₂, Ca(OH)₂. The salt 504 may include a mixture of more than onecalcium salt or magnesium calcium salt. For example, the magnesiumcalcium salt may have the formula Mg₃Ca(CO₃)₄. The calcium salt ormagnesium calcium salt can be anhydrous, substantially free of anyhydrate. Alternatively, the calcium salt and/or magnesium calcium saltcan be a hydrate, substantially free of any anhydrous. Alternatively,the calcium salt and/or calcium magnesium can be a combination ofanhydrous and hydrate. The hydrate may have the formulaCaA_(x)(H₂O)_(y), where A is an anion. The calcium salt hydrate ispreferably Ca₃(PO₄)₂(H₂O)₂ or another calcium salt hydrate.

In the composition 500, the weight percent of magnesium salt (includingboth anhydrous and hydrate):calcium salt (including both anhydrous andhydrate) is about 0%:100% to about 100%:0%, preferably about 5%:95% toabout 95%:5%, more preferably about 25%:75% to about 75%:25%, andparticularly around 45%:55% to about 55%:45%. For example, the weightpercent of magnesium:calcium is about 50%:50%. The calcium salt forestfire retardant composition may be used for a liquid concentrate.

The weight percent of the salt 504, relative to the amount oforganophosphate in the composition 500 is about 0% to about 80%. Forexample, the weight percent of the salt 504 relative to the amount oforganophosphate in the composition 500 may be about 20% to about 80%.

To control the viscosity of the composition 500, the composition 500 mayalso include at least one viscosity modifier. The viscosity modifier maybe a polyurethane, a polyvinyl alcohol, an acrylic polymer, a gum, acellulosic, a sulfonate, a polyurethane, a saccharide, a clay, anorganosilicone, or a protein, including but not limited to latex,styrene, butadiene, polyvinyl alcohol, attapulgite, bentonite,montmorillonite, algin, collagen, casein, albumin, castor oil,cornstarch, arrowroot, yuca starch, carrageenan, pullulan, konjac,alginate, gelatin, agar, pectin, carrageenan, chitosan, xanthan gum,guar gum, cellulose gum, acacia guar gum, locust bean gum, acacia gum,gum tragacanth, glucomannan polysaccharide gum, alginic acid, sodiumalginate, potassium alginate, ammonium alginate, calcium alginate,polyethylene glycol, carboxymethyl cellulose (CMC), methyl cellulose,hydroxyethyl cellulose (HEC), hydroxymethyl cellulose (HMC),hydroxypropyl methylcellulose (HPMC), ethylhydroxymethyl cellulose,hypromellose (INN), cetyl alcohol, cetearyl alcohol, acrylic microgel,or acrylic amide wax.

In one embodiment, the forest fire retardant composition 500 includes afirst viscosity modifier. The first viscosity modifier may be apolysaccharide gum.

In another embodiment, the forest fire retardant composition 500includes both the first viscosity modifier (discussed above) and asecond viscosity modifier. The second viscosity modifier may be achemically substituted cellulose.

The weight percent of the viscosity modifier, relative to the amount oforganophosphate in the composition 500 is about 0% to about 5%,preferably about 0% to about 4%, more preferably about 0% to about 3%,and more specifically about 0% to about 2%. For example, the weightpercent of viscosity modifier, relative to the amount of organophosphatein the composition 500, may be about 0.05% to about 5.0%.

The forest fire retardant formulation 500 may further include a strongbase, including but not limited to magnesium hydroxide (Mg(OH)₂),calcium hydroxide (Ca(OH)₂), sodium hydroxide (NaOH), lithium hydroxide(LiOH), barium hydroxide (Ba(OH)₂), sodium carbonate (Na₂CO₃), orpotassium hydroxide (KOH). The strong base may act as a flame retardantin the composition 500. Alternatively (or in addition), the strong basemay be used to control the pH of the composition 500. The weight percentof strong base, relative to the amount of organophosphate in thecomposition 500 is about 0.05% to about 60%. For example, the weightpercent of strong base, relative to the amount of organophosphate in thecomposition 500 may be about 0.05% to about 3%. In an alternativeexample, the weight percent of strong base, relative to the amount oforganophosphate may be about 20% to about 60%.

To control the pH of the composition 500, the composition 500 may alsoinclude buffering agents such as organic amines including but notlimited to triethanolamine (C₆H₁₅NO₃), diethanolamine, monoethanolamine,or monoethylene glycol. The weight percent of the organic amine,relative to the amount of organophosphate in the composition 500, isabout 0.25% to about 5.0%, preferably about 0.5% to about 4.5%, morepreferably about 0.75% to about 4.0%, and specifically about 1.0% toabout 3.5%. For example, the weight percent of the organic amine,relative to the amount of organophosphate in the composition 500, isabout 1.0% to about 3.0%.

The composition 500 may also include surfactant components such assodium dodecyl sulfate (SDS), sodium lauryl sulfate (SLS), sodium4-dodecylbenzenesulfonate (SDBS), 4-dodecylbenzenesulfonic acid, sodiumoctyl sulfate, butylnaphthalenesulfonic acid sodium salt, potassiumoleate, or a combination of more than one surfactant, to reduce surfacetension and increase the spreading and wetting properties of the forestfire retardant composition 500. The weight percent of surfactant,relative to the amount of organophosphate in the composition 500, isabout 0.005% to about 5.0%, preferably about 0.01% to about 4%, morepreferably about 0.02% to about 3%, and more specifically about 0.05% toabout 2.5%. For example, the weight percent of surfactant, relative tothe amount of organophosphate in the composition 500, is about 0.06% toabout 2.4%, and specifically about 0.08% to about 2.32%.

The composition 500 may also include adjuvants including but not limitedto triethanolamine, propylene glycol, propylene carbonate, RJ-7033,RJ-7077, Silwet HS-312, Silwet HS-604, Silwet 625, Silwet 641, SilwetPD, polyethylene glycol, or polypropylene glycol, or a combination ofthe above.

The composition 500 may also include a pigment such as titanium dioxide.The titanium dioxide may act as a pigment, for example, to provide awhite pigment. The titanium dioxide may also act as a photo-responsivematerial to create opacity by scattering light or by protecting thecomponents of the forest fire retardant composition 500 from UVdegradation.

The composition 500 may also include a pigment that is a colorant. Thecolorant may be a fugitive colorant, a non-fugitive colorant, or acombination of the two. The composition 500 has a first hue which is acolor, i.e., either colorless or a color which blends with the normalvegetation and/or ground in the drop zone. This first hue may be grey orwhite or a combination of the two. The colorant initially colors thecomposition 500 to a second hue which contrasts with the hue of theground vegetation. The colorant may be a fugitive component such as adye or a dye which is dispersed in a matrix (i.e., a pigment), whichfades over time and under ambient field conditions to a colorless orless highly colored hue. Preferably the colorant is one that iscompatible with magnesium salt or calcium salt such as colorants thathave been used in de-icing, dust control, or fertilizers. The fugitivecolorant may fade over time with exposure to sunlight.

Several fugitive component dyes and pigments can be used as a colorant.For example, many water-soluble dyes fade rapidly and there areso-called fluorescent pigments (fluorescent dyes encapsulated in a resinintegument) which are suspended in forest fire retardant compositionsand which also fade rapidly to provide a fugitive effect. Examples offugitive dyes and pigments include, but are not limited to, C.I. BasicRed I dye, 6BL dye, Basic Violet II dye, Basic Yellow 40, acid fuchsin,basic fuchsin, new fuchsin, acid red 1, acid red 4, acid red 8, acid red18, acid red 27, acid red 37, acid red 88, acid red 97, acid red 114,acid red 151, acid red 183, acid red 183, fast red violet 1B base,solvent red, Rhodamine B, Rhodamine 6G, Rhodamine 123, erythrosine B,Basacryl red, Phloxine B, rose Bengal, direct red 80, direct red 80,Sudan red 7B, Congo red, neutral red, Fluorescent Red Mega 480,Fluorescent red 610, Fluorescent red 630, Fluorescent Red Mega 520,Pylaklor Red S-361, Pylaklor Scarlet LX-6364A Pylam Bright Red LX-1895Pylam Coral LX-1801, FD&C Red #3, FD&C Red #4, FD&C Red #40, FD&C Red #4Lake, D&C Red #33, D&C Red #33 Lake, and encapsulated-dye pigments whichare available commercially, e.g., the “AX” series pigments, supplied byDay-Glo Color Corp., Cleveland, Ohio. The dye may be Liquitint 564(λ=564 nm) or Liquitint Agro Pink 564 (λ=564 nm) from Milliken & Company(Spartanburg, S.C.).

The colorant may be a colorant from Greenville Colorants (New Brunswick,N.J.) or Milliken & Company (Spartanburg, S.C.). For example, thecolorant is a colorant that is compatible for use with magnesium salt,such as colorants used in magnesium salt dust-control androad-stabilization formulations, or in magnesium salt de-icingformulations. The colorant may be Elcomine Scarlet NAS, ElcomineScarlaet NAS EX, or Iron Oxide GC-110P from Greenville Colorants. Thecolorant may be a combination of Liquitint 564 and Iron Oxide GC-110P.

The colorant of the composition 500 may be a dye or includeencapsulated-dye fugitive pigments without ultraviolet absorbers.Compared to water soluble dyes, encapsulated-dye pigments are lesslikely to permanently stain the normal vegetation and/or ground in thedrop zone. The fugitive component is present in an amount which providesa color (second hues) to the forest fire retardant composition 500 whichis contrasts with the color of the vegetation and/or ground in the dropzone (normally green, blue-green and/or brown). Advantageously, thesecond hue is red, orange or pink. The color of the dye may be red,orange, purple, pink or any combination of the four. Preferably, the dyeis one that is compatible with organophosphate and magnesium salt.

The colorant may also include a non-fugitive component, i.e., acomponent which is insoluble in the carrier liquid and which, ifcolored, does not necessarily fade after aerial application of theforest fire retardant composition 500. The non-fugitive component of thecolorant is present in an amount sufficient to improve the aerialvisibility of the composition when it is first applied to thevegetation. However, the non-fugitive component is present in less thanan amount which prevents the composition from thereafter fading aneutral color. The colorant may be a combination of the fugitive andnon-fugitive components. The non-fugitive component in the forest fireretardant composition 500 may be iron oxide (Fe₂O₃ and/or Fe₃O₄). Theiron oxide may be present in combination with the fugitive colorantdescribed above and titanium dioxide or it may be present alone.

The weight percent of pigment, such as titanium dioxide, colorant, orIron Oxide or Iron Oxide Black, relative to the amount oforganophosphate in the composition 500, is about 0.25% to about 20%,preferably about 0.5% to about 18%, more preferably about 0.75% to about16%, and more specifically about 1.0% to about 14%. For example, theweight percent of pigment, relative to the amount of organophosphate inthe composition 500, is about 1.2% to about 12%.

The weight percent of dye, relative to the amount of organophosphate inthe composition 500, is about 0.02% to about 3.0%, preferably about0.025% to about 2.0%, more preferably about 0.05% to about 1.5%, andmore specifically about 0.075% to about 1.2%. For example, the weightpercent of dye, relative to the amount of organophosphate in thecomposition 500, is about 0.3% to about 1.1%.

The composition 500 may also include a glow-in-the-dark additive. Theglow-in-the-dark additive improves the visibility of the fire-retardantcomposition during periods of darkness. Nighttime visibility of thecomposition is improved, for example, to the naked human eye and/orusing imaging equipment such as goggles. The glow-in-the-dark additivecan include one or more phosphorescent additives that impartsphotoluminescence properties to the forest fire retardant composition500. The phosphorescent additive may exhibit fluorescence and/orphosphorescence. The phosphorescent additive may be charged withsunlight or artificial lighting, such as UV radiation or Fluorescentlighting. The phosphorescent additive may emit light in the visiblelight region or in the ultraviolet region. Alternatively, thephosphorescent additive may emit light in the near infrared region andbe visualized using infrared goggles. Examples of the phosphorescentadditive include LumiNova, LumiNova Green (G), LumiNova G PS-2, LumiNovaBlue Green (BG), a zinc sulfide pigment, or mixtures thereof. The amountof the glow-in-the-dark additive, relative to the amount of composition500 is about 100 g/1000 L to about 1000 g/1000 L, preferably about 200g/1000 L to about 800 g/1000 L, and more preferably about 300 g/1000 Lto about 700 g/1000 L. For example, the amount of the glow-in-the-darkadditive, relative to the amount of composition 500 is about 350 g/1000L to about 550 g/1000 L.

The glow-in the-dark additive may also include one or more fluorophores.The fluorophore(s) may exhibit fluorescence and/or phosphorescence. Thefluorophore(s) may be visible in the near infrared region (i.e., 700nm-1700 nm wavelength of light). Visualization can be achieved usingnear infrared goggles. Examples of fluorophores include CH1055(4.8-Bis(2-(4-(bis(4-(2-carboxyethyl)phenyl)amino)phenyl)-5H-[1,2,5]thiadiazolo[3,4-f]benzo[c][1,2,5]thiadiazole),as well as Cy7 or Cy7.5, or mixtures thereof.

The composition 500 may also include mineral oil. The mineral oil mayhelp reduce dusting during handling of the dry concentrate 501.

The composition 500 may optionally include other ingredients, such asspoilage inhibitors, flow conditioners, anti-foaming agents, foamingagents, stability additives, biocide, thickening agents, surfactants,adjuvants, corrosion inhibitors other than those of the corrosioninhibiting system, opacifying pigments, additional coloring agents,liquid carrier, and water.

Forming the Dry and Liquid Concentrates

The dry components of the forest fire retardant composition 500 arebatch mixed in a tumbler to form a dry concentrate 501. Alternatively,the dry concentrate 501 may be mixed using continuous mixing equipment.The mixing should be controlled to ensure that all of the dry componentsare adequately dispersed. First, any dry ingredients (solidorganophosphate, salt, viscosity modifier, titanium dioxide, surfactant,colorant, and dye) are mixed together. Then, any remaining ingredients(liquid organophosphate, triethanolamine, and Wintrol® SAM-H90) areslowly added to the mixture while mixing. The dry concentrate 501 isthen stored, substantially in the absence of air and/or externalmoisture, in a sealed bag having a plastic liner. For example, eachsealed bag can contain about 2,000 pounds of the dry concentrate 501during storage and shipment to the point of use (e.g., airfield).Alternatively, the dry concentrate 501 may be stored in lined one-tontote sacks or super sacks. Air-sealed bags with a plastic liner suppliedby Semi-Bulk Systems Inc. (St. Louis, Mo.) can be used. Alternatively,an air-permeable moisture barrier can be used, such as a barrier made ofa silicone material. The dry concentrate 501 is substantially free ofwater. The dry composition 501 is chemically stable under normaltemperatures and pressures. The dry concentrate 501 should be protectedfrom exposure to humidity and moisture on moisture-proof air pallets orunder a water-resistant tarp during storage.

The liquid concentrate 502 can be formed by adding water, othersolvent(s) or aqueous solutions to the composition when it is prepared.Alternatively, the liquid concentrate 502 may be formed by the additionof water or other solvent to the dry concentrate 501. The water may betap water or water from other convenient water sources. Alternatively,the liquid concentrate 502 may be formed upon absorption of moisture bythe dry concentrate 501 if the dry concentrate 501 is deliquescent.Alternatively, the liquid concentrate 502 may be formed by mixing aliquid organophosphate with dry components. Alternatively, if a dry salt504 is not present in the dry concentrate 501, then a salt 505 may beadded during the process of converting the dry concentrate 501 to theliquid concentrate 502. Alternatively, in the absence of dry concentrate501, a salt 505 may be added to the liquid concentrate 502 in theprocess of its preparation. The salt 505 may be a dry salt or a liquidsalt. For example, to produce the liquid concentrate 502, a liquid salt505 is added to the dry concentrate 501 (with or without the addition ofmore water or solvent beyond that contained in the liquid salt). Theliquid salt may be a concentrated solution of magnesium salt, calciumsalt and/or magnesium calcium salt, including any liquid solutions madeusing the dry salt 504. The weight percent of the salt 505 in the liquidsalt solution is about 10% to 60%, preferably about 15% to 55%, morepreferably about 20% to about 50%, and particularly about 22% to about45%, or about 25% to about 40%, or about 26% to about 33%. For example,the amount of magnesium salt, calcium salt and/or magnesium calcium saltin the liquid salt solution is at or near the maximum soluble limit ofmagnesium salt, calcium salt or magnesium calcium salt, respectively.

Any dry components and/or the dry concentrate 501 are first mixed todisperse the components in the dry blend before any liquid additions.The dry components and/or the dry concentrate 501 is agitated to preventclumping of the dry components when batch mixed with water or othersolvent to form the liquid concentrate 502. Alternatively, any drycomponents and/or the dry concentrate 501 may be mixed with water orother solvent to form the liquid concentrate 502 using continuous mixingequipment. The mixing should be controlled to ensure that all of the drycomponents are adequately dispersed and hydrated to ensure that theformulation is maintained. Alternatively, the water, liquidorganophosphate, liquid salt solution 505, or solvent may be added byspraying onto a ribbon of well-mixed dry ingredients. For example, thewater, liquid organophosphate, liquid salt solution 505, or othersolvent could be sprayed onto the dry components while traveling acrossa conveyor belt. Once mixed, the liquid concentrate 502 is then stored,substantially in the absence of air and/or external moisture, in asealed container. For example, the sealed container for storage andshipment to the point of use (e.g., airfield) may be a 1,000 L tote, a5-gallon pail or a 55-gallon drum. Air-sealed bags with a plastic linersupplied by Semi-Bulk Systems Inc. (St. Louis, Mo.) can be used.Alternatively, an air-permeable moisture barrier can be used, such as abarrier made of a silicone material. The liquid concentrate 502 ischemically stable under normal temperatures and pressures.

The dry concentrate 501 and/or the liquid concentrate 502 may besupplied as part of a kit that includes a sealed container for storageand shipment, substantially in the absence of air and/or externalmoisture (e.g., 1,000 L tote, a 5-gallon pail or a 55-gallon drum, linedone-ton tote sacks or super sacks, including a plastic liner) andinstructions for using the dry concentrate 501 or the liquid concentrate502 to form the final diluted product 503 (described below). In the casewhere the final diluted product 503 is to be applied on a localizedscale by homeowners or local officials, for example, the kit may containa tank for mixing and applying the final diluted product 503 (e.g., a1-2 gallon hand-held or 4 gallon backpack or 5 gallon cart-stylecontainer with an applicator wand and/or hose, or a 15-25 gallon tankcapable of being mounted on or pulled behind an all-terrain vehicle ortruck), and instructions for using the dry concentrate 501 and/or theliquid concentrate 502 to form and apply the final diluted product 503.

Forming the Final Diluted Product

The final diluted product 503 is formed either directly from the dryconcentrate 501 by mixing the dry concentrate 501 with water or bymixing the liquid concentrate 502 with water. The dry concentrate 501 orthe liquid concentrate 502 is shipped to the point of use (e.g.,airfield), where it is diluted with water or other solvent to form thefinal diluted product 503. The dry concentrate 501 is added slowly intoroom temperature (or cooler) water with stirring. The liquid concentrate502 is designed for addition to water in a volume ratioconcentrate:water of about 1.00 to 2.50 to about 1.00 to about 6.00. Thewater may be tap water or water from other convenient water sources. Theproduct is mixed using the current mixing equipment available to theuser, including the USFS.

The final diluted product 503 can also be prepared on a commercial batchscale by combining the dry concentrate 501 or the liquid concentrate 502with a measured amount of water in an appropriate mix vessel such as anagitated mix tank. The rate of addition of solid or liquid concentrateto water should be controlled to assure efficient mixing of theconcentrate and the water. Alternately, a continuous process may beconducted by introducing the dry concentrate 501 or liquid concentrate502 into a water stream via a vacuum eductor system where the ratio offlow through the eductor port to the bypass flow is roughly 1:9.Downstream mixing should be accomplished to avoid product settling inthe receiving tank, or the receiving tank itself should be vigorouslycirculated to facilitate solution and adequate hydration of the dryconcentrate 501.

The final diluted composition 503 can also be batch mixed by feeding thedry concentrate 501 or the liquid concentrate 502 into a well-circulatedmix-batch tank. Alternatively, the final diluted composition 503 may bemixed using continuous mixing equipment. Mix tank agitation may beprovided via an overhead mechanical stirring apparatus or alternativelyby a circulation pump sized to provide turbulent mixing. Alternatively,a venturi-type vacuum eductor mixer or an in-line high-shear mixer canbe used. For batch mixing, the mix water is agitated or circulated toprovide efficient mixing, then a one-ton sack of dry concentrate 501 isadded slowly, typically by suspending the sack over the mix tank (via afork lift or by other manner), and opening the discharge spout on thesack to allow product to flow out of the sack into the mix solution. Theaddition rate should be controlled to avoid settling of the solidconcentrate in the mix tank. The final diluted product 503 is in a formsuitable to fight forest fires via aerial- or ground-based application.

The dry concentrate 501 or the liquid concentrate 502 is diluted withwater so that the final diluted product 503 has an organophosphateconcentration of about 1% to about 50%, preferably about 3% to about45%, more preferably about 5% to about 35%, and more specifically about7% to about 32%. For example, the weight percent of the organophosphatein the final diluted product 503 is about 8% to about 30%.

The liquid concentrate 502, may be diluted at about a 1.00:2.50,1.00:4.00, 1.00:5.00, or 1.00:6.00 (liquid concentrate:water) to formthe final diluted product 503. The liquid concentrate 502 is dilutedwith water so that the final diluted product 503 has an organophosphateconcentration of about 1% to about 5%, preferably about 3% to about 45%,more preferably about 5% to about 40%, and more specifically about 7% toabout 35%. For example, the weight percent of the organophosphate in thefinal diluted product 503 is about 8% to about 30%.

The viscosity of the liquid concentrate 502 should have a viscosity thatpermits it to be pumped through a hose. The viscosity of the liquidconcentrate 502 at 70° F. may be in the range of about 100 cP to about10,000 cP, preferably about 500 cP to about 7,000 cP, more preferablyabout 750 cP to about 5,000 cP, and more specifically about 1,000 cP toabout 3,000 cP. For example, the viscosity of the liquid concentrate 502at 70° F. may be about 2,000 cP.

The final diluted product 503 should have a viscosity that permits it tobe pumped through a hose and applied to a forest fire. The viscosity ofthe final diluted product 503 at 70° F. may be in the range of about 1to about 1,000 cP, preferably about 100 to about 700 cP, more preferablyabout 120 to about 500 cP, and more specifically about 150 cP to about400 cP.

EXAMPLES Example 1

Example 1 includes an organophosphate and does not include a salt. InExample 1 below, a liquid concentrate 502 is prepared containing theamounts of ingredients listed in Table 1 below. The values in Table 1can be varied by ˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or˜3.0%, or ˜3.5%, or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 1 Liquid Concentrate according to Example 1 Weight Percent of EachIngredient in Ingredient Wet Concentrate Salt 0.00% Organophosphate50.00% Pigments 1.00% Magnesium Hydroxide 0.32% Triethanolamine(C₆H₁₅NO₃) 0.58% Corrosion Inhibitor 0.58% Dye 0.21% Surfactant 0.04%Viscosity modifier 0.00% Water 47.27%

An Example 1 final diluted product 503 is prepared by mixing the liquidconcentrate 502 of Example 1 with water in a volume ratioconcentrate:water of 1.00 to 1.50. According to Example 1 approximately1 pound of the liquid concentrate 502 is mixed with 1.50 pounds of waterto prepare the final diluted product 503. The final diluted product 503of Example 1 may be prepared by mixing the liquid concentrate 502 ofExample 1 with water in a volume ratio concentrate:water of about 1.0 toabout 1.1 to about 1.0 to about 3.0.

The weight percent of the salt 504, relative to the amount oforganophosphate in the composition 500 of Example 1 is about 0%.

The weight percent of strong base, relative to the amount oforganophosphate in the composition 500 of Example 1 is about 0.05% toabout 10%, preferably about 0.1% to about 8%, more preferably about0.15% to about 6%, and more specifically about 0.2% to about 5%. Forexample, the weight percent of strong base, relative to the amount oforganophosphate in the composition 500, is about 0.25% to about 4.0%,and specifically about 0.32%.

The amounts of the ingredients in the Example 1 final diluted product503 are listed in Table 2 below. The values in Table 2 can be varied by˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%,or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 2 Final Diluted Product according to Example 1 Weight Percent ofEach Ingredient in Ingredient Wet Concentrate Salt 0.00% Organophosphate19.98% Pigments 0.40% Magnesium Hydroxide 0.13% Triethanolamine(C₆H₁₅NO₃) 0.23% Corrosion Inhibitor 0.23% Dye 0.08% Surfactant 0.02%Viscosity modifier 0.00% Water 78.93%

Example 2

Example 2 includes an organophosphate and a salt. In Example 2 below, aliquid concentrate 502 is prepared containing the amounts of ingredientslisted in Table 3 below. The values in Table 1 can be varied by ˜0.1%,˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%, or˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 3 Liquid Concentrate according to Example 2 Weight Percent of EachIngredient in Ingredient Wet Concentrate Salt 25.00% Organophosphate50.00% Pigments 2.00% Magnesium Hydroxide 0.64% Triethanolamine(C₆H₁₅NO₃) 1.00% Corrosion Inhibitor 1.00% Dye 0.40% Surfactant 1.16%Viscosity modifier 0.60% Water 18.20%

An Example 2 final diluted product 503 is prepared by mixing the liquidconcentrate 502 of Example 2 with water in a weight ratioconcentrate:water of 1.00 to 4.00. According to Example 2 approximately1 pound of Example 2 502 is mixed with 4 pounds of water to prepare theExample 2 final diluted product 503. The final diluted product 503 ofExample 2 may be prepared by mixing the liquid concentrate 502 ofExample 2 with water in a volume ratio concentrate:water of about 1.0 toabout 2.0 to about 1.0 to about 6.0.

The weight percent of the salt 504, relative to the amount oforganophosphate in the composition 500 of Example 2 is about 0% to about60%, more preferably 5% to 50%, and particularly about 10% to about 40%.For example, the weight percent of the salt, relative to the amount oforganophosphate in the composition 500 is about 15% to about 35%, andspecifically about 25%.

The weight percent of strong base, relative to the amount oforganophosphate in the composition 500 of Example 2 is about 0.05% toabout 10%, preferably about 0.1% to about 8%, more preferably about 0.2%to about 6%, and more specifically about 0.3% to about 5%. For example,the weight percent of strong base, relative to the amount oforganophosphate in the composition 500, is about 0.4% to about 4.0%, andspecifically about 0.64%.

The amounts of the ingredients in the Example 2 final diluted product503 are listed in Table 4 below. The values in Table 4 can be varied by˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%,or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 4 Final Diluted Product according to Example 2 Weight Percent ofEach Ingredient in Ingredient Wet Concentrate Salt 5.00% Organophosphate10.00% Pigments 0.40% Magnesium Hydroxide 0.13% Triethanolamine(C₆H₁₅NO₃) 0.20% Corrosion Inhibitor 0.20% Dye 0.08% Surfactant 0.23%Viscosity modifier 0.12% Water 83.64%

Example 3

Example 3 includes an organophosphate and a salt at a high mix ratio. InExample 3 below, a liquid concentrate 502 is prepared containing theamounts of ingredients listed in Table 5 below. The values in Table 5can be varied by ˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or˜3.0%, or ˜3.5%, or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 5 Liquid Concentrate according to Example 3 Weight Percent of EachIngredient in Ingredient Wet Concentrate Salt 30.00% Organophosphate50.00% Pigments 2.40% Magnesium Hydroxide 0.77% Triethanolamine(C₆H₁₅NO₃) 1.35% Corrosion Inhibitor 1.35% Dye 0.40% Surfactant 0.50%Viscosity modifier 0.72% Water 12.51%

An Example 3 final diluted product 503 is prepared by mixing the liquidconcentrate 502 of Example 3 with water in a weight ratioconcentrate:water of 1.00 to 5.00. According to Example 3 approximately1 pound of Example 3 502 is mixed with 5 pounds of water to prepare theExample 3 final diluted product 503. The final diluted product 503 ofExample 3 may be prepared by mixing the liquid concentrate 502 ofExample 3 with water in a volume ratio concentrate:water of about 1.0 toabout 3.0 to about 1.0 to about 7.0.

The weight percent of the salt 504, relative to the amount oforganophosphate in the composition 500 of Example 3 is about 10% toabout 80%, more preferably 15% to 75%, and particularly about 20% toabout 70%. For example, the weight percent of the salt, relative to theamount of organophosphate in the composition 500 is about 25% to about60%, and specifically about 50%.

The weight percent of strong base, relative to the amount oforganophosphate in the composition 500 of Example 3 is about 0.1% toabout 10%, preferably about 0.2% to about 8%, more preferably about 0.3%to about 6%, and more specifically about 0.4% to about 5%. For example,the weight percent of strong base, relative to the amount oforganophosphate in the composition 500, is about 0.5% to about 4.0%, andspecifically about 0.77%.

The amounts of the ingredients in the Example 3 final diluted product503 are listed in Table 6 below. The values in Table 6 can be varied by˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%,or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 6 Final Diluted Product according to Example 3 Weight Percent ofEach Ingredient in Ingredient Wet Concentrate Salt 5.00% Organophosphate8.33% Pigments 0.40% Magnesium Hydroxide 0.13% Triethanolamine(C₆H₁₅NO₃) 0.23% Corrosion Inhibitor 0.23% Dye 0.07% Surfactant 0.08%Viscosity modifier 0.12% Water 85.42%

Example 4

Example 4 includes an organophosphate and a metal hydroxide and does notinclude a salt. In Example 4 below, a liquid concentrate 502 is preparedcontaining the amounts of ingredients listed in Table 7 below. Thevalues in Table 7 can be varied by ˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%, or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 7 Liquid Concentrate according to Example 4 Weight Percent of EachIngredient in Ingredient Wet Concentrate Salt 0.00% Organophosphate40.00% Pigments 4.80% Magnesium Hydroxide 20.00% Triethanolamine(C₆H₁₅NO₃) 0.80% Corrosion Inhibitor 0.80% Dye 0.28% Surfactant 0.10%Viscosity modifier 0.60% Water 32.62%

An Example 4 final diluted product 503 is prepared by mixing the liquidconcentrate 502 of Example 4 with water in a weight ratioconcentrate:water of 1.00 to 3.00. According to Example 4 approximately1 pound of Example 4 502 is mixed with 3 pounds of water to prepare theExample 4 final diluted product 503. The final diluted product 503 ofExample 4 may be prepared by mixing the liquid concentrate 502 ofExample 4 with water in a volume ratio concentrate:water of about 1.0 toabout 1.5 to about 1.0 to about 4.5.

The weight percent of the salt 504, relative to the amount oforganophosphate in the composition 500 of Example 4 is about 0%.

The weight percent of strong base, relative to the amount oforganophosphate in the composition 500 of Example 4 is about 5% to about60%, preferably about 10% to about 50%, more preferably about 12% toabout 40%, and more specifically about 15% to about 35%. For example,the weight percent of strong base, relative to the amount oforganophosphate in the composition 500, is about 15% to about 30%, andspecifically about 20%.

The amounts of the ingredients in the Example 4 final diluted product503 are listed in Table 8 below. The values in Table 8 can be varied by˜0.1%, ˜0.5%, or ˜1.0%, or ˜1.5%, or ˜2%, or ˜2.5%, or ˜3.0%, or ˜3.5%,or ˜4.0%, or ˜4.5%, or ˜5.0%.

TABLE 8 Final Diluted Product according to Example 4 Weight Percent ofEach Ingredient in Ingredient Wet Concentrate Salt 0.00% Organophosphate10.00% Pigments 1.20% Magnesium Hydroxide 5.00% Triethanolamine(C₆H₁₅NO₃) 0.20% Corrosion Inhibitor 0.20% Dye 0.07% Surfactant 0.03%Viscosity modifier 0.15% Water 83.16%

Methods of Use

The forest fire retardant compositions of Examples 1 to 4 may be used tosuppress, retard, or contain a forest fire. The forest fire retardantcompositions of Examples 1 to 4 function as superior forest fireretardants and suppressants compared to the PHOS-CHEK® brand long-termfire retardants (LTR) which have previously been qualified for use bythe USFS. A list of the PHOS-CHEK® USFS Qualified long-term fireretardants is given in Table 9.

TABLE 9 List of PHOS-CHEK ® USFS Qualified LTR Products USFS QualifiedLTR Products List Description PHOS-CHEK ® MVP-Fx Dry Concentrate,Gum-Thickened, High and Medium Viscosity, High Visibility, FugitiveColor PHOS-CHEK ® MVP-F Dry Concentrate, Gum-Thickened, High and MediumViscosity, Standard Fugitive Color PHOS-CHEK ® P100-F Dry Concentrate,Gum-Thickened, High and Medium Viscosity PHOS-CHEK ® 259-Fx DryConcentrate, Gum-thickened, Low Viscosity, High Visibility, Fixed TankHelicopter Powder Concentrate PHOS-CHEK ® 259-F Dry Concentrate,Gum-thickened, Low Viscosity PHOS-CHEK ® LC-95A-R Wet Concentrate,Gum-Thickened, Low Viscosity PHOS-CHEK ® LC-95A-Fx Wet Concentrate,Gum-Thickened, Low Viscosity, High Visibility, Fugitive ColorPHOS-CHEK ® LC-95A-F Wet Concentrate, Gum-Thickened, Low ViscosityPHOS-CHEK ® LC-95-W Wet Concentrate, Gum-Thickened, Low Viscosity, RedIron Oxide, medium Viscosity Liquid Concentrate

The forest fire retardant compositions of Examples 1 to 4 may containone, two or more fire-retardant mechanisms of action as a result of thetwo or more possible fire retardant ingredients, includingorganophosphate and hydrated salt. The organophosphate reduces thecombustion temperature and creates a robust char layer that acts as aphysical barrier to combustion. The hydrated salt pulls heat from thefire and produces free water as it dehydrates in the flames.

The organophosphate in the forest fire retardant compositions ofExamples 1 to 4 prevent complete combustion of flammable vegetation.Organophosphate reduces the temperature at which the fire burns.Additionally, the organophosphate increases the amount of char residuecontent. As the organophosphate burns, it releases phosphoric acid,which contributes to the dehydration of the surrounding polymer andvegetation, and results in the formation of a robust char layer at thesurface of the vegetation. The robust char layer acts as a physicalbarrier that blocks heat and oxygen from the flammable surface. The charlayer buffers the flammable vegetation from the fire's heat and slowsthe fire spread.

The hydrated salt in the forest fire retardant compositions of Examples2 to 4 pull energy out of forest fires at they convert the hydrates ofthe hydrated salt to free water. For example, the final dilutedcomposition 503 may include magnesium salt hydrate. Once the finaldiluted composition 503 has dried after application, the magnesium salthydrate of the composition effectively retards continued combustion.Magnesium hydroxide interferes with the burning process through therelease of inter gases (such as water vapor). In this process aprotective char layer is formed or the amount of energy available forthe spread of fire is reduced through energy absorption. Magnesium salthydrate is deliquescent, absorbing sufficient moisture from the air toform a liquid solution. Examples 2 to 4 are also self-rehydrating. Thelarger the difference between the relative humidity of the atmosphereand the critical relative humidity, the faster the water is rehydrated.Generally, the relative humidity on a wildland fire is lowest during theday and recovers during the night. In moderate burning condition, thenighttime relative humidity recovery will rise to 50%-70%. This is anenvironmental condition that exists almost every night on wildfires,thereby allowing magnesium salt hydrate to absorb moisture from the airand pull it in to the fuel bed leading to its improved forest fireretardant capabilities. The forest fire retardants of Examples 2 to 4will start to recover water at a lower relative humidity and recover fora longer time every burning period. Calcium salt has a similar retardingefficiency to magnesium salt. Thus, calcium salt has potential use as along-term liquid fire retardant alone or in combination with magnesiumsalt. Aluminum hydroxide functions in a similar mechanism to magnesiumhydroxide and has potential use as a long-term fire retardant alone orin combination with magnesium hydroxide.

The PHOS-CHEK® LTR products of Table 9 use a similar mechanism to thatused by the organophosphate in forest fire retardant 500 to slow thespread of fire. Diammonium phosphate (DAP), an ingredient in PHOS-CHEK®LTR products, can promote the formation of a robust char layer onflammable vegetation that blocks the fire's heat and oxygen to slow thefire spread. In contrast to the forest fire retardant 500, DAP containsammonium functional groups. Ammonium-functionalized compounds may causelong-term adverse effects in the aquatic environment. Additionally,ammonium-functionalized compounds may release ammonia gas uponcombustion. Ammonia gas is acutely toxic to humans and wildlife and maycause burns to the skin and eyes. Additionally, ammonia is very toxic toaquatic organisms. Forest fire retardant 500 is substantially free ofany ammonia or ammonium functional groups and is much less toxic tohumans and wildlife.

Direct Attack

In a direct attack, the final diluted composition 503 is applied on thefire line. The final diluted composition 503 is a thickened watersuppressant which contains water to cool and suppress the fire. Forexample, when the final diluted composition 503 includesorganophosphate, the organophosphate lowers the temperature of the flamefront as it burns, releasing phosphoric acid. The organophosphatepromotes the formation of a robust char layer that acts as a buffer tofurther combustion of flammable vegetation. Additionally, if, forexample, the final diluted composition 503 includes a magnesium salthydrate, the water molecules of the magnesium salt hydrate thermallydehydrate in an endothermic reaction, absorbing heat from the fire asthe reaction progresses and lowering the temperature of the flame front.

Indirect Attack

In an indirect attack, the final diluted composition 503 is applied infire containment lines at a significant distance from the fire line. Theindirect fire lines are built, and the fire is allowed to burn intothem. The long-term fire retardant must be effective even after thewater in the composition has evaporated. In an indirect attack, thefinal diluted composition 503 is applied to vegetation. When the flamefront reaches vegetation treated with the final dilute concentration503, the organophosphate lowers the temperature of the flame front as itburns, releasing phosphoric acid. The organophosphate promotes theformation of a robust char layer that acts as a buffer to furthercombustion of flammable vegetation. Additionally, if, for example, thefinal diluted composition 503 includes a magnesium salt hydrate, thefinal diluted composition 503 is hygroscopic and self-rehydrating. Asthe water in the final diluted composition 503 evaporates, the saltconcentration increases until it reaches its saturation level. When theflame front reaches vegetation treated with the final dilutedcomposition 503, the hydrated water molecules cleave-off in anendothermic reaction, absorbing heat from the fire as the reactionprogresses and lowering the temperature of the flame front.

Field Handling and Measurement

The forest fire retardant compositions of Examples 1 to 4 can bedelivered to the field either as the dry concentrate 501, liquidconcentrate 502, or as the final diluted composition 503. The finaldiluted composition 503 can be tested prior to application in the fieldto confirm proper organophosphate content. A refractometer can be usedto test the final diluted composition 503. A density measurement canalso be used to test the final diluted composition 503. A density ofless than 9.1 pounds per gallon may indicate a proper organophosphatecontent. A pH measurement can also be used to test the final dilutedcomposition 503. A pH of about 6 to about 10 may indicate a properorganophosphate content. A viscosity measurement can also be used totest the final diluted composition 503. A viscosity measurement of about150 to about 2,500 cP may indicate a proper organophosphate content.

Aerial Application

The final diluted composition 503 may be deposited via aerialapplication from an airplane or helicopter. The airplane may be afixed-wing multi-engine aircraft, a fixed-wing single engine airtanker(SEAT), a large airtanker (LAT), a very large airtanker (VLAT), or anunmanned aircraft system (UAS). The helicopter may be a fixed-tankhelicopter (HF) or it may be a helicopter bucket (HB). The final dilutedcomposition 503 may be deposited in an indirect attack to build aretardant line before a forest fire or directly to a forest fire viaaerial application.

Ground Application

The final diluted composition 503 may be deposited via ground-basedequipment, for example via ground application from a truck or groundengine (G). The final diluted composition 503 may be deposited in anindirect attack to build a retardant line before a forest fire or it maybe deposited directly to a forest fire via ground application.

Clean Up Procedure

The dry concentrate 501 can be cleaned by broom and/or vacuum. The dryconcentrate 501 should be kept dry during cleaning to minimize colorstaining that may occur when the dye is hydrated. When the dryconcentrate 501 is exposed to water, the product can be cleaned with theuse of a granular chemical absorbent material, or if proper drainage isavailable, by rinsing surfaces clean with adequate amounts of water. Dyecoloration may be removed from surfaces by treatment with liquid or drydetergent. The final diluted composition 503 can be cleaned with soap orliquid detergent and water. The color of the dye can be neutralized bysodium hypochlorite or washed with liquid detergent.

CONCLUSION

All parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and the actual parameters, dimensions,materials, and/or configurations will depend upon the specificapplication or applications for which the inventive teachings is/areused. It is to be understood that the foregoing embodiments arepresented primarily by way of example and that, within the scope of theappended claims and equivalents thereto, inventive embodiments may bepracticed otherwise than as specifically described and claimed.Inventive embodiments of the present disclosure are directed to eachindividual feature, system, article, material, kit, and/or methoddescribed herein.

In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure. Othersubstitutions, modifications, changes, and omissions may be made in thedesign, operating conditions and arrangement of respective elements ofthe exemplary implementations without departing from the scope of thepresent disclosure. The use of a numerical range does not precludeequivalents that fall outside the range that fulfill the same function,in the same way, to produce the same result.

Also, various inventive concepts may be embodied as one or more methods,of which at least one example has been provided. The acts performed aspart of the method may in some instances be ordered in different ways.Accordingly, in some inventive implementations, respective acts of agiven method may be performed in an order different than specificallyillustrated, which may include performing some acts simultaneously (evenif such acts are shown as sequential acts in illustrative embodiments).

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification, all transitional phrasessuch as “comprising,” “including,” “carrying,” “having,” “containing,”“involving,” “holding,” “composed of,” and the like are to be understoodto be open-ended, i.e., to mean including but not limited to. Only thetransitional phrases “consisting of” and “consisting essentially of”shall be closed or semi-closed transitional phrases, respectively, asset forth in the United States Patent Office Manual of Patent ExaminingProcedures, Section 2111.03.

In the claims, as well as in the specification, any ingredient listed inan open-ended list of ingredients shall not be negated or avoided by theaddition of water or other solvent or reactant that might cause achemical change to such ingredient. Thus, for example, even though it isknown that an anhydrous salt becomes hydrated in the presence of water,the inventors hereby act as their own lexicographers, so that anycomposition “including” or “comprising” an “anhydrous” salt is intendedto cover both a dry composition substantially free of water in which thesalt has substantially no water of hydration, as well as any wetcomposition formed by the addition of water which causes the anhydroussalt to become hydrated (or to undergo some other change). Both beforeand after the addition of water or other ingredient, the compositionshall be regarded, for purposes of the specification and claims, ascomprising an “anhydrous” salt irrespective of any hydration, solvation,or other change caused by the addition of water or other ingredient. Thesame applies for any ingredient recited in an open-ended list whichmight be chemically changed by the addition of water or other ingredientto the open-ended list.

1. A forest fire retardant composition, comprising: an organophosphatecomprising at least one phosphate ester bonded to an organic molecule; acorrosion inhibitor; wherein: the organic molecule comprises one to fivemonosaccharide units; each monosaccharide unit is about 2 to about 40carbon atoms; and the composition is substantially free of ammonium. 2.The forest fire retardant composition of claim 1, wherein the organicmolecule comprises one or two monosaccharide units.
 3. The forest fireretardant composition of claim 1, wherein the monosaccharide unit is atleast one of glucose or fructose.
 4. The forest fire retardantcomposition of claim 1, further comprising a salt comprising at leastone of magnesium salt, calcium salt, or magnesium calcium salt; whereinan anion in the salt comprises at least one of carbonate or phosphate.5. The forest fire retardant composition of claim 1, further comprisinga strong base in the forest fire retardant composition in a weightpercent of about 0.05% to about 60% relative to the amount oforganophosphate in the forest fire retardant composition.
 6. The forestfire retardant composition of claim 1, wherein the corrosion inhibitorinhibits the corrosion of at least one of brass, iron, aluminum, ormagnesium.
 7. The forest fire retardant composition of claim 6, whereinthe corrosion inhibitor comprises one or more azoles.
 8. The forest fireretardant composition of claim 1, further comprising a pigment presentin the forest fire retardant composition in a weight percent of about0.25% to about 20% relative to the amount of organophosphate in theforest fire retardant composition.
 9. The forest fire retardantcomposition of claim 1, further comprising a colorant present in theforest fire retardant composition in a weight percent of about 0.02% toabout 3.0% relative to the amount of organophosphate in the forest fireretardant composition.
 10. The forest fire retardant composition ofclaim 1, further comprising a viscosity modifier present in the forestfire retardant composition in a weight percent of about 0.05% to about5.0% relative to the amount of organophosphate in the forest fireretardant composition.
 11. The forest fire retardant composition ofclaim 1, further comprising a buffering agent in the forest fireretardant composition in a weight percent of about 0.25% to about 5.0%relative to the amount of organophosphate in the forest fire retardantcomposition.
 12. The forest fire retardant composition of claim 1,further comprising a glow-in-the-dark additive.
 13. The forest fireretardant composition of claim 1, wherein: the composition is in theform of a concentrate further comprising water, wherein: the water ispresent in the concentrate in an amount having a weight percent of about5% to about 70% relative to the total weight of the concentrate; and theorganophosphate is present in the concentrate in an amount having aweight percent of about 15% to about 90% relative to the total weight ofthe concentrate.
 14. A kit comprising: a sealed container which containsthe forest fire retardant composition of claim 13 substantially in theabsence of external moisture; and instructions for using the compositionto make a final diluted product useful to suppress, retard, or containforest fires.
 15. The forest fire retardant composition of claim 1,further comprising a surfactant present in the forest fire retardantcomposition in a weight percent of about 0.02% to about 3% relative tothe amount of organophosphate in the forest fire retardant composition.16. The forest fire retardant composition of claim 15, wherein thesurfactant comprises at least one of sodium dodecyl sulfate (SDS),sodium lauryl sulfate (SLS), sodium 4-dodecylbenzenesulfonate (SDBS),4-dodecylbenzenesulfonic acid, sodium octyl sulfate,butylnaphthalenesulfonic acid sodium salt, or potassium oleate.
 17. Aforest fire retardant composition, comprising: an organophosphatecomprising at least one phosphate ester bonded to an organic molecule,wherein the organic molecule comprises at least one monomer unit ofabout 2 to about 40 carbon atoms; a corrosion inhibitor; and aglow-in-the-dark additive, wherein the composition is substantially freeof ammonium.
 18. The forest fire retardant composition of claim 17,further comprising a salt comprising at least one of magnesium salt,calcium salt, or magnesium calcium salt; wherein an anion in the saltcomprises at least one of carbonate or phosphate.
 19. The forest fireretardant composition of claim 17, further comprising a strong base inthe forest fire retardant composition in a weight percent of about 0.05%to about 60% relative to the amount of organophosphate in the forestfire retardant composition.
 20. The forest fire retardant composition ofclaim 17, wherein the corrosion inhibitor inhibits the corrosion of atleast one of brass, iron, aluminum, or magnesium.
 21. A kit comprising:a sealed container which contains the forest fire retardant compositionof claim 17 substantially in the absence of external moisture; andinstructions for using the composition to make a final diluted productuseful to suppress, retard, or contain forest fires.
 22. A forest fireretardant composition, comprising: an organophosphate comprising atleast one phosphate ester bonded to an organic molecule, wherein theorganic molecule comprises at least one monomer unit of about 2 to about40 carbon atoms; a corrosion inhibitor; and a colorant present in theforest fire retardant composition in a weight percent of about 0.02% toabout 3.0% relative to the amount of organophosphate in the forest fireretardant composition, wherein: the composition is substantially free ofammonium; and the colorant comprises at least one of a fugitive colorantor a non-fugitive colorant.